Regioselective Synthesis of Phenanthridines via Pd(II)-Catalyzed Annulative C(sp²)–H Activation

Abstract

A robust synthesis of phenanthridines has been described via Pd(II)-catalyzed domino C(sp2)–H activation/N-arylation using oxime esters with aryl acyl peroxides in a highly regioselective manner. This protocol is compatible with acetophenone as well as benzophenone-derived oxime esters and allows modular construction of functionalized phenanthridines with wide tolerance of electronic functionality. Further transformations were conducted to synthesize key building blocks, and control experiments were performed to understand the plausible reaction mechanism.

Electro‐oxidative Methylation of 2‐Isocyanobiaryls Using N,N‐dimethylformamide (DMF) as Carbon Source: Synthesis of 6‐Methylphenanthridines

“…Further investigation revealed that the types of supporting electrolytes also significantly affected the reaction efficiency ( [20][21][22][23][24][25]. Decreasing of the current density from 17.3 mA cm À 2 to 13.5 and 9.6 mA cm À 2 or increasing it to 23.1, 30.8, 38.5 and 57.7 mA cm À 2 afforded 2 a in modest to low yields (Table 1, entries [26][27][28][29][30][31]. Slightly lower yield was observed when the reaction temperature was raised to 80 °C (Table 1, entry 32).…”